Some (such as The Big Short author Michael Lewis) see high-frequency, algorithm-based stock trading as a serious threat to the economy. There's a concern that big trading firms are cornering the market by paying for ultra-fast connections that give them unfair advantages, such as front running (exploiting knowledge of advance orders from customers) and otherwise closing transactions before most rivals. Those financial heavyweights might not get to abuse the system if IEX has its way, though. It just opened a US stock exchange that aims to prevent these computer-driven attempts to game the system.

To begin with, every trade is slowed down by 350 microseconds -- you can't just pay for a faster connection to beat the competition. Not that you could if you wanted to. IEX bans trading houses from paying for servers that live closer to the stock matching engine, so wealthier outfits can't just buy their way to success.

Will it succeed? Not necessarily. There are 13 American stock exchanges now that IEX is around, and getting companies to trade there may be difficult when the the likes of NASDAQ and the New York Stock Exchange are more popular. But if it does catch on, it could be the key to changing a financial system that's often driven more by automation than human decisions.